For the curious, here's how I turned the numbers into letter grades.

First, the University's instructions as to what the grades mean:

       A: Represents achievement that is outstanding relative to the
          level necessary to meet course requirements.

       B: Represents achievement that is significantly above the level
          necessary to meet course requirements.

       C: Represents achievement that meets the course requirements in
          every respect.  

       D: Represents achievement that is worthy of credit although it
          fails to fully meet the course requirements.

       F: Represents failure.

The grade weights are as on the syllabus.  The lowest homework score
was dropped, as were the lowest 3 clicker scores.    

The standard grade scale you're familiar with: 93%=A, 83%=B, etc.

There are two ways to curve this.  The "flat" method takes the highest
grade in the course, calls that a "100%", so 93% of that high score is
an A, 83% of it a B, etc.

The second way is to use Gaussian statistics (the old "bell curve").  In
this method, a bell curve is fit to the grades.  The letter grades are
assigned to percentiles based upon the bell curve.

The percentage needed to get a given grade is compared between these two
methods, and the one which gives you the student the best grade is
used. 

Note that UMD doesn't allow grades of A+ or D- (they don't say anything
about F+/- though, hmmm).